Sequence Stratigraphy, Geomechanics, Microseismicity, and Geochemistry Relationships in Unconventional Resource Shales

Roger M. Slatt

Gungoll Chair Professor of Petroleum Geology and Geophysics and

Director, Institute of Reservoir Characterization

University of Oklahoma




Cyclical sedimentation patterns are common in unconventional resources shales, whether they be carbonate- or siliciclastic-dominated. In many resource shales the cyclical patterns have been related to eustatic sea level fluctuations, even though these fluctuations may sometimes be obscured by tectonic overprint. The cyclicity is reflected in repetitive sedimentation patterns which represent alternating relatively shallow/oxic- and deeper/anoxic-water deposition.  Typical cyclicity might occur in the form of alternating clay/organic-rich and quartz/calcite-rich strata. In more carbonate-rich sequences, organic-rich marls might alternate with organic-poor limestones. This cyclicity can occur at a variety of stratigraphic scales and provides a sequence stratigraphic framework for mapping, correlation, and interpretations. Incised valley/karst fill may provide a localized, thicker, more  organic-rich stratigraphic section (‘sweet spot’), than adjacent areas.

Within the context of geomechanics, these cyclical strata are termed ‘brittle-ductile couplets’. Using the Barnett and Woodford shales as examples, clay/organic-rich intervals tend to be relatively ductile (relatively low Young’s Modulus and high Poisson’s ratio) and cleaner quartz/calcite-rich intervals tend to be relatively brittle (relatively high Young’s Modulus and low Poisson’s ratio. In carbonate-rich deposits such as the Eagle Ford Formation, re-crystallized, TOC-poor limestones tend to be stronger and more brittle than TOC-rich marls.

Within the context of microseismic, microseisms may be vertically stratified or layered, with some horizons containing more events than other horizons. This stratification has been related to brittle-ductile couplets in at least one area, and placed within a sequence stratigraphic framework.

Within the context of geochemistry, ductile strata tend to contain more TOC, and are thus better potential HC source rocks, than brittle strata, which contain less TOC. Biomarkers (geochemical fingerprints) are useful for interpreting sources and environments of deposition of organic matter, and ultimately used for environmental zonation of shales. 

Using these principles and observations, it is possible to build a sequence stratigraphic framework from multiple data sets to map and correlate brittle and ductile strata, organic-/hydrocarbon-rich zones, and more fracturable stratigraphic intervals. Such a framework can provide a guide for optimal horizontal drilling landing zones.

Speaker Roger Slatt, Ph.D.
Vitae Roger M. Slatt Gungoll Family Chair Professor of Petroleum Geology and Geophysics and Director, Institute of Reservoir Characterization School of Geology and Geophysics, University of Oklahoma, Norman, OK 73091 (ph. 405-802-9220; FAX 405-325-3140;    EDUCATION AND TRAINING: A.A.    San Francisco City College, 1961 B.A.    California State Univ. San ...


Roger M. Slatt

Gungoll Family Chair Professor of Petroleum Geology and Geophysics and Director, Institute of Reservoir Characterization

School of Geology and Geophysics, University of Oklahoma, Norman, OK 73091

(ph. 405-802-9220; FAX 405-325-3140;



A.A.    San Francisco City College, 1961

B.A.    California State Univ. San Jose, 1965

M.S.    University of Alaska, 1967

Ph.D.   University of Alaska, 1970



2009-pres.        Gungoll Family Chair Professor of Petroleum Geology and Geophysics,                                        University of Oklahoma

2007-09           Lew and Myra Ward Chair in Reservoir Characterization

2005-07           Gungoll Family Chair Professor of Petroleum Geology and                                                              GeophysicsUniversity of Oklahoma

2000-05           Director, School of Geology and Geophysics, University of Oklahoma

1992-2000       Professor and Head, Dept. Geology and Geological Engineering, Colorado                                    School of Mines

1990-92           Manager, Reservoir Evaluation, ARCO International Oil and Gas Co.

1983-90           Director of Lithostratigraphic Evaluation, Director of Reservoir Geology,                                       and Manager of Stratigraphic Exploration Research, ARCO Research and                                      Technical Services Co.

1980-83           Stratigraphy Research Manager, Cities Service Co.

1978-80           Senior Research Geologist, Atlantic Richfield Co.

1976-78           Visiting Assistant Prof. of Geology, Arizona State Univ.

1970-76           Post-doc Fellow, Assist./Assoc. Prof. of Geology, Memorial University of                          Newfoundland (Canada)



Slatt, R.M., 2013, Stratigraphic reservoir characterization for petroleum geologists,

geophysicists, and engineers, 2nd Edition, Elsevier Publ. Co. 671p.. (1nd Edition published 2006, 492p.

Slatt,  R.M. and C. Zavala (eds.) 2011, Sediment transfer from shelf to deepwater, AAPG

            Studies in Geology 61 (co-published with SEPM),  214p.

Slatt, R.M. and others (eds.), 2006,Reservoir Characterization: Integrating Technology and   

            Business Practices, 26th Ann. Gulf Coast Section SEPM Found. Bob F. Perkins Research

            Conference, 1257p. CD Book

Weimer, P. and R.M. Slatt, 2006, Introduction to the petroleum geology of deepwater

            settings, AAPG Studies in Geology Series  (CD book), 816p.

Slatt, R.M.(ed.), 1998, Compartmentalized reservoirs in Rocky Mountain basins, Rocky

            Mtn. Assoc. Geol. 1998 Symposium Vol., 250 p.

O'Brien, N. R, Slatt, R. M., 1990, Argillaceous Rock Atlas, Springer-Verlag, N.Y. 141p.


R.M. Slatt and N.R. O'Brien, 2013, Microfabrics related to porosity development, sedimentary and diagenetic processes, and composition of unconventional resource shale reservoirs as determined by conventional scanning electron microscopy, AAPG Memoir 102, Chapter 5, p. 37-44.

Cadena, A.F. and R.M. Slatt, 2013, Seismic and sequence stratigraphic interpretation of the area of influence of the Magdalena submarine fan, offshore northern Colombia, Interpretation, Aug. (inaugural edition), p. SA53-74.

Slatt, R.M., Rodriguez, N.D., 2012, Comparative sequence stratigraphy and organic geochemistry of gas shales: Commonality or coincidence?, Journal of Natural Gas Science and Engineering (2012), doi:10.1016/j.jngse.2012.01.008

Slatt, R.M., P.R. Philp, N. O’Brien, Y. Abousleiman, P. Sing, E.V. Eslinger, R. Perez, R. Portas, E. T. Baruch, K. J. Marfurt, and S. Madrid-Arroyo, 2012, Pore-to regional-scale, integrated characterization workflow for unconventional gas shales, , in Breyer, J. (ed) Shale Reservoirs—Giant Resources for the 21st Century, AAPG Memoir 97, p. 127-150,

Slatt, R.M., 2011, Important geological properties of unconventional resource shales, Cent. Europ. J. Geosciences, p. 435-448.

Slatt, R.M. and N.R. O’Brien, 2011, Pore types in the Barnett and Woodford gas shales: contribution to understanding gas storage and migration pathways in fine grained rocks, AAPG Bull. P. 2017-2030.

Slatt, R.M. and Y. Abousleiman, 2011, Merging sequence stratigraphy and geomechanics for unconventional gas shales, The Leading Edge, March 2011, p. 274- 282. Also presented at AAPG 2011 Annual Convention and won AAPG Best Poster Award.

Pyles, D.R., J.P.M. Syvitski, and R.M. Slatt, 2010, Applying the concept of stratigraphic grade to reservoir architecture along the shelf-to-basin profile: An outcrop perspective: Marine and Petroleum Geology, p.1-23.

Slatt, R.M., and R.J. Davis, 2010, Calibrating borehole image and dipmeter logs with outcrops and behind-outcrop cores: case studies and applications to deepwater deposits, in Poppelreiter, M., C. Garcia-Carballido, M. Kraaijveld, W. Epping, and C. Xu (eds), AAPG Memoir 92: Dipmeter and Borehole Image Log Technology, p. 167-194.

Zou, Fuge, and R.M. Slatt, 2010. An integrated approach to characterization and modeling of the Jackfork Group at the Baumgartner Quarry area, western Arkansas and its implications to global deepwater exploration and production, The Shale Shaker (also submitted to AAPG Bulletin).




-Present numerous short courses and field trips on Reservoir Characterization, Sequence Stratigraphy, Petroleum Geology of Deepwater Depositional Systems, and Geology of   Unconventional Resource Shales to national and international government organizations and petroleum companies.

-Member American Association of Petroleum Geologists, Society of Petroleum Engineers,            Geological Society of American, Society of Exploration Geophysicists, and Society of            Sedimentary Geology (SEPM)

-Director of current research program in Unconventional Resource Shales ($245,000 from             petroleum industry) involving 15 students.

-Advisor to approximately 70 M.S. and Ph.D. graduates while at OU.

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Tue, Jan. 13, 2015
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